Why do interviewers ask freshers to test a pen?

To see whether you ask questions before testing, think in categories (functional, negative, usability, durability, safety) and give checkable expected results. The pen itself does not matter.

How many cases should I say out loud?

Ask your clarifying questions, name the categories, give two or three cases in each, and offer to go deeper in one area. Reading out thirty cases is too long for a spoken answer.

What is a negative test case for a pen?

Using it in a way it is not meant for, and checking it fails safely: writing on oily paper, pressing very hard, or leaving it in a hot car. The expected result is that it does not leak or break, even if it does not write.

Test cases for a pen (interview question)

Assumes a retractable (click) ballpoint pen with blue ink, a 0.7 mm tip, a pocket clip and a replaceable refill, sold to students and office users. Every number below is an example; ask for the real specification.

How to answer in an interview

Pause and ask questions first: what kind of pen (ballpoint, gel, fountain), who is it for, what does the product claim (smooth writing, waterproof ink, a writing length), what price range, and is it refillable? The answers change the tests: a pen for exam halls needs a long ink life and no leaks; a pen for children needs safety checks. Then walk through categories: writing, ink, mechanism and body, durability, safety and packaging. Finish with which cases you would run first.

Scope and test data

Test a sample of pens from more than one batch, not a single pen. Use the paper the target users actually use (a ruled school notebook and plain A4 printer paper) plus a few unusual surfaces. The writing-length check needs either a lab writing machine or an agreed manual method; agree the method first. These are designed cases, not an execution report.

Writing

ID	Category	Test case	Expected result
P01	Functional	Write a paragraph on plain A4 paper	Continuous line with no skipping; ink colour matches the label
P02	Functional	Click and start writing immediately on a new pen	Ink flows on the first stroke, or within the number of strokes the spec allows
P03	Functional	Write holding the pen upright and at a shallow angle	Line stays continuous at both angles
P04	Functional	Sign your name quickly ten times	No skips, no blobs at the end of strokes
P05	Functional	Measure the line width with a magnifier and scale	Consistent with the stated 0.7 mm tip
P06	Compatibility	Write on a ruled notebook, glossy paper, an envelope and cardboard	Writes on the supported surfaces; any surface it cannot handle is noted against the spec
P07	Negative	Write on a vertical surface and with the tip pointing up	Matches the claim; if no claim is made, record the result without failing it
P08	Performance	Write until the ink runs out, by machine or the agreed method	Meets the stated writing length, if one is claimed

Ink

ID	Category	Test case	Expected result
P09	Functional	Rub a line with a finger after the agreed drying time	No smudge
P10	Functional	Put a drop of water on dried writing	Meets the water-resistance claim; if none, record how far it runs
P11	Functional	Write on the target notebook paper and look at the back	No bleed-through
P12	Negative	Store pens tip down, tip up and in a shirt pocket for 24 hours	No leak from the tip or the body
P13	Negative	Leave the pen in a hot parked car for a few hours, then cool it	No leak; writes normally once cooled
P14	Negative	Keep the pen in a refrigerator for a few hours	Writes within a few strokes after taking it out
P15	Functional	Write with several pens from the same batch side by side	Same ink colour across pens

Mechanism and body

ID	Category	Test case	Expected result
P16	Functional	Click the button the agreed number of times (for example 5,000)	Tip still extends and retracts every time
P17	Functional	Press down hard while writing	Tip does not slip back into the body mid-stroke
P18	Functional	Clip the pen to a shirt pocket and a notebook cover repeatedly	Clip grips firmly and does not crack or bend out of shape
P19	Functional	Replace the refill with the correct refill, then try a wrong size	Correct refill fits and writes; the wrong size does not fit or is clearly loose
P20	UI	Write for 30 minutes, including with slightly damp hands	Grip comfortable; pen does not slip
P21	UI	Rub the printed brand and colour marking with a thumb many times	Print does not rub off in normal use
P22	UI	Write with the left hand	Ink does not smear more than the drying-time claim suggests

Durability

ID	Category	Test case	Expected result
P23	Negative	Drop the pen from desk height onto a tiled floor several times	Body does not crack; pen still writes
P24	Negative	Carry the pen in a back trouser pocket and sit down	Body and clip survive, or the result is recorded against the spec
P25	Negative	Write on oily or wet paper	Does not write well, but the tip is not damaged and works on dry paper afterwards

Safety and packaging

ID	Category	Test case	Expected result
P26	Security	Run a finger along the body, clip and button	No sharp edges or burrs
P27	Security	Check the ink and material documents for a school product	Certificates required in the target market are present and current
P28	Security	Check small detachable parts on a pen sold for children	Parts meet the child-safety rules of the target market
P29	UI	Read the pack: colour, tip size, MRP and other mandatory declarations	All present, legible and matching the pen inside
P30	Functional	Open a multi-pen pack	Count and colours match the pack label

What to prioritise

For an exam-hall pen, P01, P02, P08 and P12 decide whether people buy it again. In an interview, the mistake is to jump straight to "write with it" and stop. Another is to give expected results like "should work properly": say what you will look for, such as "no skipping" or "no smudge after the drying time".

Test cases for a pen